Typically, gas turbine engines include a compressor for compressing air, a combustor for mixing the compressed air with fuel and igniting the mixture, and a turbine blade assembly for producing power. Combustors often operate at high temperatures that may exceed 2,500 degrees Fahrenheit. Typical turbine combustor configurations expose airfoils, such as turbine blade and vane assemblies, to these high temperatures. As a result, the airfoils must be made of materials capable of withstanding such high temperatures. In addition, the airfoils often contain cooling systems for prolonging the life of the airfoils and reducing the likelihood of failure as a result of excessive temperatures.
Typically, airfoils are formed from an elongated portion, a leading edge, and a trailing edge. The inner aspects of most airfoils typically contain an intricate maze of cooling channels forming a cooling system. The cooling channels in the airfoils receive air from compressors of turbine engines and pass the air through the airfoils. The cooling channels often include multiple flow paths designed to maintain all aspects of the airfoils below design temperature. However, centrifugal forces and air flow at boundary layers often prevent some areas of the airfoils from being adequately cooled, which results in the formation of localized hot spots. In addition, contaminants in the cooling fluid flowing through the airfoils can clog impingement orifices and film cooling orifices in the airfoils, which can also produce localized hot spots. Localized hot spots, depending on their location, can reduce the useful life of a turbine blade and can damage a turbine blade to an extent necessitating replacement of the blade.
Operating turbine engines having airfoils with plugged impingement cooling orifices or film cooling orifices can result in catastrophic damage to the airfoil or the turbine engine, or both. For instance, airfoils having plugged impingement cooling orifices or film cooling orifices operate at elevated temperatures, which if elevated to too high a temperature can cause failure of the airfoils. During failure of an airfoil, portions of the airfoil break off and strike downstream components of a turbine engine, thereby damaging the airfoil. Thus, a need exists for a system for identifying airfoils in turbine engines having plugged cooling orifices before failure of these airfoils.